1. Field of the Invention
The present invention relates to a method and apparatus to control the regeneration of a diesel aftertreatment device, and, more particularly, to a method and apparatus used to regenerate a diesel aftertreatment device using an injection pump to provide the pressurized fuel thereto.
2. Description of the Related Art
In modern low emission diesel engines, the fuel and air mixture is controlled and an exhaust gas recirculation system is utilized to reduce the NOx during steady state engine operation. Typically, the exhaust system directs the exhaust flow through a diesel oxidization catalyst, also known as a three-way catalyst, and through a diesel particulate filter. These devices are generally understood to be aftertreatment devices used to clean the exhaust before releasing the exhaust to the ambient atmosphere. Some aftertreatment devices require a burn off of the elements collected therein and, in order to accomplish this, diesel fuel is injected in some manner to facilitate the burn off.
The technology utilized to accomplish the burn off is typically expensive and complicated for the performance of the required task of regenerating, or self-cleaning the aftertreatment device, particularly for small diesel engines. The regeneration systems on large diesel engines typically use a high-pressure common rail injection system to provide the extra fuel on the exhaust stroke of the engine to thereby pump the fuel into the aftertreatment system. However, such a system is inordinately expensive for a small diesel engine.
What is needed in the art is a method and apparatus to regenerate an aftertreatment device for a small diesel engine without the need for a common rail injector system and the problems associated with that type of process.